The quality of a digital signal can be evaluated in various ways such as by measuring the number of bit errors generated by the digital signal when the digital signal is received in a receiver. One of several causes for bit errors is due to timing variations in various edges of the digital signal. These timing variations can be observed in an oscilloscope as back-and-forth movement of various edges of the digital signal. The back-and-forth movement, which is commonly referred to as jitter, can be measured on the oscilloscope and/or by using other jitter measurement instruments.
Traditional jitter measurements typically involve the use of a measurement instrument to detect transitions in the digital signal crossing a certain detection threshold (the transitions indicate edges in the digital signal and these edges are examined for measuring jitter). For a differential signal, the detection threshold is typically zero volts.
Unfortunately, the use of a single detection threshold can lead to some shortcomings. For example, some traditional jitter measurements involve adapting the digital signal in order to make the digital signal suitable for applying a single detection threshold. Adapting the digital signal in this manner may involve changing a waveshape of the digital signal and/or introducing an offset voltage in the digital signal. Either of these actions may lead to misleading and/or erroneous jitter measurements being made.
It is therefore desirable to provide a solution in which rather than adapting the digital signal to the detection threshold (as done traditionally), the detection threshold is adapted to the digital signal instead.